hammond



' UNITED STATES PATENT OFFICE.

HENRY W. HAMMOND, OF LONDON, COUNTY OF MIDDLESEX, ENGLAND.

ROCK-DRILL BAR.

SPECIFICATION forming part of Letters Patent No. 237,013, dated January25, 1881.

Application filed August 19, 1880. (No model.)

To all whom it may concern Be it known that I, HENRY WOODOROFT HAMMOND,of 27 Southampton Buildings, Chancery Lane, London, County of Middlesex,England, civil and mechanical engineer, have invented as an article ofmanufacture'a new and Improved Form of Steel Bar for Mining and otherDrills, of which the following is a full, clear, and exact description,reference being had to the drawings, which form part of thisspecification.

The improved bar I propose to call Hammonds bonanza rolled drill-bar.

It has been customary heretofore to forge the end or point of theordinary steel bar into a special shape of drill required for mining,quarrying, or other purposes. This method is not only expensive andslow, but has been found to be open to other objections, such asclogging and loss of time in reforging for every few inches of the drillworn away. To

- obviate these defects it has been proposed to roll bars of steel intocertain shapes which are deemed suitable for drills, and to this classof drill-steel my invention relates.

Figurel representsa section of myimproved form of bar. Fig. 2 representsa side elevation or plan of Fig. 1. Fig. 3 represents a side elevationof the drilling end of my improved bar. Fig. 4 represents an end View ofFig. 3.

a a a a represent the cutting-edges; b b b b, the semicircular recessesin the drill-bar, by which the powdered material escapes from thedrill-hole during work, thus preventing the clogging of the drill.

The drill-bar is rolled by suitable rolls, and

therefore presents throughout its entire length the configurationrequired for the drill, the penetrating point 0 being ground, filed, orforged to shape, as desired, the shank being formed in the usual manner,or the end may be fitted or keyed in a coupling of suitable section, ifdeemed preferable.

Drills made in the manner and of the shape herein shown and describedpresent four outting-edges of the finest and best description, the bodyof the drill at the same time being excessively strong, therebypresenting greater resistance to the so-called action of springing socommon in drills formed in the ordinary manner.

One of the great advantages of my form of bar is the small amount ofsurface which requires to be ground, forged, or filed to produce a finepenetrating point. It is also evident that this improved bar isapplicable for boring, turning, and analogous purposes.

I am aware that rolled steel bars of crosslike and triangular shapewithout sharp edges are shown in patent granted J nne 8, 1880, to W. A.Sweet for drills; and such 1 do not now claim; but

What I do claim, and desire to secure by Letters Patent, is-

As a new article of manufacture, a rolled steel drill-bar of the shapeshown, having edges to a a a and semicircular recesses b b b b,substantially as specified.

HENRY WOODOROFT HAMMOND.

Witnesses:

PHILIP M. JUSTICE, ALLEN P. J ONES.

